Hi roottalk, I'm having trouble looping over entries in array variables using TTree::Draw under a specific circumstance. I've placed an example in: http://www.hep.umn.edu/~schubert/roottest/ntptest.tar.gz The example consists of three simple classes: class NtpShower : public TObject { ... Float_t fEnergy; // shower energy ClassDef(NtpShower,1) //A reconstructed shower }; class NtpEvent: public TObject { ... Int_t fEventNo; // event number Int_t fNShower; // number of showers in this event Int_t* fShwInd; //[fNShower] array of indices into shower TClonesArray ClassDef(NtpEvent,1) //A reconstructed event }; class NtpRecord:public TObject { ... TClonesArray* fShowers; //~> Array of showers TClonesArray* fEvents; //-> Array of events ClassDef(NtpRecord,1) //A reconstructed spill record }; These classes are set up so that the user can use the shower indices stored in the NtpEvent class to map back to the NtpShower objects stored in the fShowers TClonesArray. In the test program FillNtp, a tree is created with a single main branch to hold NtpRecord objects, split at level = 99, One NtpRecord is generated and the fShowers array is filled with 3 NtpShowers: // shower 0 has fEnergy 10 // shower 1 has fEnergy 20 // shower 2 has fEnergy 30 and 4 NtpEvents: // event 0 has 2 showers with fShwInd values of 0 &1 // event 1 has 0 showers // event 2 has 1 shower with fShwInd value of 2 // event 3 has 0 showers Now I try to use the arrays in a Draw (or Scan loop) and I find that the results aren't what I expect. For example, tree -> Scan("fShowers[fEvents[].fShwInd[0]].fEnergy","fEvents[].fNShower > 0"); yields: *********************************** * Row * Instance * fShowers[ * *********************************** * 0 * 0 * 10 * *********************************** ==> 1 selected entry instead of the expected 2 entries. I can get 2 entries if I leave off the selection string, but I find I need this selection string to avoid array out of bounds if the first argument to Scan or Draw becomes more complicated, e.g.: tree -> Scan("fEvents[].fNShower:fShowers[fEvents[].fShwInd[0]].fEnergy"); causes a rather enormous list of array indexing errors. Is this a bug or is there an error in the way I'm expressing the loop over the arrays? Thanks, -Sue
This archive was generated by hypermail 2b29 : Sun Jan 02 2005 - 05:50:09 MET